Omg that is so sweet! It reminds me of the cake my best friend baked for me when I turned 18. I was big into "The X-Files" at the time and I had a huge crush on David Duchovny, so she cut out his head from a magazine then hid it under the icing. She had a bunch of green icing alien heads with big black eyes on it and he was under one of them, and she'd written in icing across the top "Find the Duchovny". I love it when people do things like that. It shows how much they care for you.
Happy Birthday!